Vascular and heart diseases are among the most prominent diseases in western world. In particular, heart diseases are the leading cause of death. In recent years, a possibility to treat such illness, that became increasingly popular and successful, employs transplantation of organs or structural parts, e.g. heart valves in the case of heart valve dysfunction. However, the potential recipients far outnumber the present donors of the organs needed. Thus the growing demand creates a constant need for artificial organs or structures that can at least temporarily replace the natural organs.
Currently, synthetic implants or natural implants of animal origin are used to overcome the gap between the number of available natural donors and potential recipients. Yet, they bear quite a number of disadvantages.
Synthetic implants may lead to complications such as thrombosis, a risk which is increased due to changes in the blood flow caused by artificial heart valves. That is why patients with artificial heart valves permanently need anticoagulant medicaments. In addition, such patients are prone to infections causing life-threatening complications.
Implants of natural origin used for replacement of heart valves are usually derived from porcine or cow. The porcine or cow tissue is treated with glutar-aldehyde. These biological implants have the disadvantage that they tend to degenerate after twelve to fifteen years. Thus, they are not suitable for younger patients. Another risk inherent to biological implants is the transmission of pathogens, in particular viruses. It is also possible, that biological implants trigger unwanted and often fatal immune reactions by the host immune system, since the material may be recognized as foreign tissue.
A further disadvantage of artificial implants such as heart valves lies in the fact that these structures are not living structures and therefore cannot undergo any repair or growth processes as needed by the host. Especially younger patients thus need multiple surgeries which itself increases the mortality risk.
Thus, there is a need for implants comprising artificial structures, e.g. a scaffold, that can be used to culture cells. By culturing cells on such a scaffold one tries to prepare hybrid structures which may serve as implants and provide specific functions. Such processes are also termed tissue engineering.
Tissue engineering includes the preparation of suitable scaffolds that are biocompatible and preferably degradable. Such hybrid implants should at least temporarily provide a biomechanical structure that allows the cultured cells to form the tissue or structure needed as far as this is possible.
Biocompatible materials employed in prior art for the above describes purposes are polyglycolic acid (PGA), polyhydrooctanoate (PHO) and polyhydroxyalcanoate (PHA). However, neither of these materials unites all the properties needed in terms of mechanical stability and biocompatibility. Implants comprising PGA are brittle. Implants comprising PHA lack the required rate of degradability and degrade only very slowly in a patient's body.